Process of extracting tungsten and similar metals from their ores.



D. I. II I. E. GILES. PROCESS OF EXTRACTING 'IUNGSTEN AND SIMILAR METALSFROM THEIR ORES. APPLICATION FILED FEB. II, I918.

%9@ 3 Patented Feb. 4, 1919.

FIIBJL- WITNESSES INVENII'OHS A I 1; mm 0.4 w

'of other ores,

OF MGKEESPORT, PENNSYLVANIA.

PROCESS OF EXTRACTING TUNGSTEN AND SIMILAR METALS FROM THEIR, (IRES.

11,293,4lil3.

Specification of Letters Patent.

Patented Feb. 4, 11919.

Application filed February 11, 1918. Serial No. 216,559.

To all whom it may concern:

'Be it known that we, DAVID JoHN GILES and JAMES EARL GILES, residentsof McKeesport, in the county of Allegheny and State of Pennsylvania,have invented a new and useful Improvement in Processes of ExtractingTungsten and Similar Metals from Their Ores, of which the following is aspecification.

This invention relates to a process of extracting from their ores suchmetals as tungsten, vanadium, uranium and molybdenum. The object of theinvention is to provide a process for extracting the above named metalsfrom their ores whereby the metals can be produced in a substantiallypure form and at a much lesser cost than by processes heretofore in use.

In general, the process consists in forcing a re-action between the oreand a water solution of some alkaline compound whose hydroxid radical isreplaceable by the metal of the ore, thus forming an alkaline-metalsolution, and thereafter treating said solu tion with calcium compounds,first, to precipitate the impurities as insoluble compounds, and then toprecipitate the metal in the form of an insoluble calcium-metalcompound.

As the alkaline compound, it is preferred to use sodium hydrate (NaOH)on account of the energy of its re-action, but other alkaline compoundscan be used, such as soda ash, z'. 6.. sodium carbonate, ammoniumhydrate, or the like; or various potassium compounds can be used. As thecalcium compounds for treating the solution, to precipitate theimpurities and the metals, use is made of lime in some form, preferablymilk of lime, but, if desired, calcium chlorid or any compound of theother alkaline earth metals may be used instead.

The process will be explained for the extraction of tungsten from itsore with the use of sodium hydrate as the alkaline compound and milk 'oflime for the precipitating agent. The re-actions for the treatmentagents, will be similar to those which will be described.

In carrying out the process the tungsten ore should be ground to a smallsize and then treated with a water solution of sodium hydrate preferablin a closed vessel to which heat is appliedithus generating steam in thevessel and producing a pressure and a way is to crush the ore to or bythe use of other re higher temperature than can be gotten by boiling inan open vessel. Under these condltions the re-action takes placevigorously, but the same result can be obtained by boiling in an openvessel, provided more time is given and the ore is ground very fine.This step of the process can be carried out in an ordinary autoclave,but the preferred as small a size as convenient and .then charge thesame, together with the sodium hydrate solution, into a closed revolvingdrum provided with balls or cylinders, wherein the ore is pulverizedWhile being subjected to the foregoing action of the re-agent understeam pressure. A modified ball-mill is suitable for this purpose. Inthe accompanying drawing one form of mill suitable for this purpose isillustrated, Figure 1 showing the same in side elevation and Fig. 2showing the same in part in end elevation and in part in transversesection.

The mill illustrated comprises the drum or cylinder 1 rotatably mountedon rollers ordisks 2 arranged in two series, one on each side of thedrum, as shown in Fig. 2, and secured to shafts 4, one of which ispositively driven, such as by means of gearing 5 driven from anysuitable source of power, the drum being rotated by the frictionalengagement of the driven rollers or disks with collars 6 on the drum.This drum is formed of cast or other iron and is provided with cast ironor similar liners 7 which are removable to compensate for wear. In thedrum are a number of balls or round rods 8 which serve to pulverize thecrushed ore as the drum rotates. The drum is tightly closed and thematerial is charged thereinto through man-holes 9 in one of the headsthereof. Heat is applied to the drum in any suitable way, such as bymeans of gas burn ers 10 or the like. A pressure gage 11 is provided inthe head to control the pressure.

arious forms of apparatus can obviously be used and that illustrated ismerely one convenient form. It has been found that a short treatment ofthe ore in such an apparatus serves to effectively grind the ore to theproper fineness and to efl'ect the extraction of the metal at the sametime. The pressure which we prefer to maintain in the apparatus is aboutpounds per square inch.

The treatment hydrate solution of the ore in the sodium in the closed.vessel 1n the manner specified, z". e., under pressure and at a higherheat than can be obtalned by b011- ing in an open vessel, acceleratesthe re-action whereby the hydroxid radical of the sodium hydrate isreplaced by the tungsten, forming a solution 0 cording to the followingequat10ns:

This solution is then separated from the gangue, as by decanting, butpreferably by filtering. In the reaction taking place in the drum somesilica and phosphorus go into solution as sodium silicate and sodiumphosphate, and these must be removed if the metals-are to be produced ina substantially pure form. This is done by treating the solution comingfrom the drum, when at a relatively low temperature, such as at roomtemperature, to-wit, in the nelghborhood of 60 or degrees Fahrenheit, bydiluting to about eight-tenths of one per cent. (1%) of sodium hydrate,and adding the calcium compound. At this temperature the milk of lime orother calcium compound can be added in excess and precipitates thephosphorus and silica as insoluble calcium compounds, but does notprecipitate the tungsten or other metal. This reaction is according tothe following equations:

The solution is then filtered and is again treated with the calciumcompound, to-Wit, the milk of lime, and its temperature is raised toapproximately 200 degrees Fahrenheit, and at this higher temperature thetungsten or other metal is prec pltated as insoluble calcium tungstate,which is apowder when dry. This reaction is according to the followingformula:

This precipitate is separated from the liquid by decanting orfiltering,and is then treated with hydrochloric acid and produces calcium chloridand tungstic acid. This reaction is according to the following equation:

The so called hydrated tungstic acid is then washed, dried and reducedby means of carbon, giving metallic tungsten.

The sodium hydrate is recovered from the liquor from which the tungstenhas been precipitated, by evaporating and concentrating to the strengthdesired, thus again producing a sodium hydrate solution which can beused to treat a fresh batch of ore.

Likewise, the calcium chlorid which is produced by treating the calciumtungstate with the hydrochloric acid, is also a bysodium tungstate, ac-

product which can be sold as a separate product or used in place of themilk of lime to precipitate the tungsten from the solution of sodiumtungstate, according to the following equation:

The process is very economical. Practically all of the re-agents arerecovered, and the process can be carried out expeditiously and by useof very simple and easily procured apparatus. The process of extractingthe metal from the ore is alkaline throughout and hence unprotected ironor steel apparatus can be used. It requires no jigging or otherconcentration of the ores before treatment and is applicable to allkinds of ores of the metals specified, even very low grade ore.

Among the tungsten ores to which it is applicable are ferberite, i. 0.iron tungstate, hiibnerite, z". e. manganese tungstate, wolframite,which is a mixture of manganese tungstate and iron tungstate, scheelite,'5. 6. calcium tungstate, as well as to practically all of the ores ofvanadium, uranium and molybdenum.

What we claim is 2- 1. The process of extracting metals of the characterspecified from their ores and purifying the same, which consists intreating the ore with a solution of an alkaline compound, therebyreplacing the hydroxid radical of the alkaline compound by the metal ofthe ore, then diluting the solution and adding to it at a relatively lowtemperature a calcium compound, thereby precipitating insoluble calciumcompounds of silica and phosphorus, and adding to the residual liquor ata higher temperature a calcium compound, thereby precipitating aninsoluble calcium-metal compound.

2. The process of extracting metals of the character specified fromtheir ores and purifying the same, which consists in treating the orewith a solution of sodium hydrate, thereby forming a sodium compound ofthe metal of the ore, then diluting the solution and adding to it at arelatively low temperature a calcium compound, thereby precipitatinginsoluble calcium compounds of silica and phosphorus, and adding to theresidual liquor at a higher temperature a calcium compound, therebyprecipitating an insoluble calcium-metal compound.

3. The process of extracting tungsten from its ores and purifying thesame, which consists in treating the ore with a solution of an alkalinecompound while under pressure, thereby replacing the hydroxid radical ofthe alkaline compound by the metal of the ore, formin an alkalinetungstate, then diluting the so ution and adding to it at a relativelylow temperature a calcium com pound and thereby precipitating insolublecalcium compounds of silica. and phosphorus, and adding to the residualalkaline tungstate solution at a higher temperature a calcium compound,thereby precipitating insoluble calcium tungstate.

4. The process of extracting tungsten from its ores and purifying thesame, which consists in treating the ore with a solution of sodiumhydrate, thereby forming soluble sodium tungstate, diluting saidsolution and adding thereto at a relatively low temperature a calciumcompound, thereby precipitating insoluble calcium compounds of silicaand phosphorus, and adding to the residual sodium tungstate solution ata highertemperature a calcium compound, thereby precipitating insolublecalcium tungstate.

5. The process of extracting metals of the character specified fromtheir ores, which consists in heating the ore in a solution of alkalinecompound while under pressure,

thereby replacing the hydroxid radical of the alkaline compound by themetal of the ore, separating the solution from the gangue, diluting thesolution and adding thereto at a relatively low temperature a calciumcompound, thereby precipitating insoluble calcium compounds of silicaand phosphorus, and then adding to the residual alkalinemetal solutionat a higher temperature a calcium compound, thereby forming an insolublecalcium-metal compound as a precipitate.

6. The process of extracting metals of the character specified fromtheir ores, which consists in heating the ore under pressure in asolution of sodium hydrate, thereb replacing the hydroxid radical of thesodium hydrate by the metal of the ore, separating the solution fromthegangue, diluting the solution and adding thereto at a relatively lowtemperature a calcium compound, thereby precipitating insoluble calciumcompounds of silica and phosphorus, and adding to the residualalkaline-metal solution at a higher temperature a calcium compound, 4

thereby forming an insoluble calcium-metal compound as a precipitate.

7 The process of extracting tungsten from its ore, which consists inheating the tungsten ore in a solution of an alkaline compound whileunder pressure, thereby replacing the hydroxid radical of the alkalinecompound by the metal of the ore, forming alkaline tungstate, separatingthe solution from the gangue, diluting the solution and adding to it ata relatively low temperature a calcium compound and therebyprecipitating insoluble calcium compounds of silica and phosphorus, andadding to the residual alkaline-metal solution at a higher tempera .turea calcium compound, thereby forming insoluble calcium tungstate as aprecipitate.

8. The process of extracting tungsten from its ore, which consists inheating the ore in a solution of sodium hydrate under pres sure, therebyforming sodium tungstate, separating the soluble sodium tungstatesolution from the gangue, diluting the solution and adding to it at arelatively low temperature a calcium compound, thereby precipitatinginsoluble calcium compounds of silica and phosphorus, and adding to theresidual alkaline-metal solution at a higher temperature a calciumcompound, thereby forming insoluble calcium tun'gstate as a precipitate.

In testimony whereof, We have hereunto set our hands.

DAVID JOHN GILES. JAMES EARL GILES.

Witness CARL F. MoRLocK.

